Method and device for transmitting information formed of a speech part and a data part

ABSTRACT

In a communication system for Internet protocol (IP)-based transmission of information formed of a speech part and a data part between interface units with a plurality of ports, the speech part and the data part are transmitted to separate ports of the receiving interface unit. The ports that used are allocated to each other in the communication system as corresponding ports.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based on and hereby claims priority to GermanApplication No. 100 48 167.1 filed on Sep. 28, 2000, the contents ofwhich are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method and a device for Internet Protocol(IP)-based transmission of information formed of a speech part and adata part in a communication system.

2. Description of the Related Art

As computers are integrated into communication services, IP-basedtransmission of information is also being increasingly used incommunication systems. In addition to transmitting voice information fortelephone services, information with both speech and data content isalso being transmitted for several applications, such as videoconferencing.

To ensure an optimum transmission speed or transmission bandwidth, theinformation is compressed before transmission. The speech part can becompressed with some loss. The algorithm used for this can however notbe used for the data part of the information as this would lead tounwanted loss of information.

Furthermore, it is preferable to transmit the parts using differenttransport protocols. Accordingly, the information to be transmitted isdivided into speech and data parts and transmitted separately.

FIG. 3 is a block diagram showing a device for transmitting informationin a traditional communication system. The information from a sender 10for a receiver 40 is first divided by an interface unit 20 into a speechpart and a data part and then transmitted to a second interface unit 30.The separate transmission of the parts is controlled by a controlmessage (arrow with dotted line). The arrow represents bi-directionaldata traffic as receipt is usually confirmed by a control message.

A traditional transmission operation in interface units 20 and 30 isshown in the left and right halves of FIG. 4. The first interface unit20 receives information that comprises a speech part and data part fromthe sender 10 to be transmitted to the receiver 40. In the first stage(dividing), the information is divided into its component parts. In thesecond stage (coding), the speech and data parts are compressed andformatted according to the protocols used. The speech and data parts aretransmitted to two different ports on the second interface unit 30.

So that the second interface unit 30 recognizes the identity of theparts, an appropriate control message is sent at a higher protocollevel. In this example, a H.323 message is used to inform the secondinterface unit about the two ports. H.323 is a standard that definescomponents, procedures and protocols for audio-visual communication overpacket-switched networks.

In a first stage (decoding), the second interface unit 30 interprets thereceived H.323 message and allocates the parts accordingly. In a secondstage (combining), the original information formed from the parts iscombined so that it can be forwarded to the receiver 40.

Since a connection has to be set up using the control message beforetransmission can occur, there is a time delay caused by transmitting,answering and processing the control message.

SUMMARY OF THE INVENTION

An object of the invention is to provide a method and a device thatavoids the time delay attributable to the control message.

According to the present invention in a communication system that usesInternet Protocol (IP)-based transmission of information formed of aspeech part and a data part from a first to a second interface unit, theinformation will be divided into speech and data parts and transmittedusing different ports. In the second interface unit, the correspondingtransmitted speech and data parts are allocated using dedicated ports.Corresponding information is transmitted to corresponding ports, makingan additional control message unnecessary.

In a preferred embodiment of the method, more than two ports arededicated as corresponding ports. The interface unit can thereforeselect the appropriate combination of ports required for theinformation.

In a further preferred embodiment of the method, the data part istransmitted using a Transmission Control Protocol (TCP) that guaranteesa dedicated sequence of data packets and error correction. It is furtherpreferable to transmit the speech part using a User Datagram Protocol(UDP), since UDP guarantees a higher transmission speed.

In a further embodiment of the method, the data part contains acombination of types of data, supporting various types of data andapplications.

According to a preferred embodiment of the method, the information isdivided into a speech part and a data part in the scope of the firstinterface unit. This means that the method can be used independentlyfrom the interfaces of different applications.

According to a preferred embodiment of the method, the speech part iscompressed with some loss before transmission to achieve a fastertransmission.

According to the present invention, a device in a communication systemwith two interface units with a plurality of ports realizes the requiredmethod.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects and advantages of the present invention willbecome more apparent and more readily appreciated from the followingdescription of the preferred embodiments, taken in conjunction with theaccompanying drawings of which:

FIG. 1 is a block diagram of a device according to the present inventionin a communication system,

FIG. 2 is a flowchart of a method according to the present invention forthe first and second interface units from FIG. 1,

FIG. 3 is a block diagram of a device in a standard communicationsystem,

FIG. 4 is a flowchart of a standard method for the first and secondinterface units from FIG. 3.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings, wherein like reference numerals refer to like elementsthroughout.

FIG. 1 shows a device according to the present invention with a sender10, a receiver 40, a first interface unit 20 and a second interface unit30. The information to be transmitted from the sender 10 to the receiver40 is divided into a speech part and a data part using two ports andtransmitted from the first interface unit 20 to the second interfaceunit 30. A first port is assigned for the speech part, a second for thedata part.

The left-hand side of FIG. 2 describes a sample process in the firstinterface unit 20. In a first stage (dividing), the information receivedand to be transmitted is divided into a speech part and a data part.Sequences from dual-tone multi-frequency dialing may be used ascharacterizing features for data parts. In the second stage (coding),the speech part with some loss is compressed, while the data part iscompressed without loss using an algorithm. The data part is thentransmitted using TCP and the speech part using UDP to two differentports on the second interface unit 30. Ports used for transmitting dataare allocated according to a list (definition) that assigns ports eitherindividually, in pairs or in groups to a connection.

The process in the second interface unit 30 is shown in the right-handside of FIG. 2. The speech part and the data part of the information arereceived at 30 different ports. In a first stage (decoding), the partsare decompressed separately and then assigned to one another accordingto the definition. To forward the information to the receiver 40, in asecond stage (combining), the speech part and data part are combinedinto complete information again.

As a connection between sender 10 and receiver 40 normally comprises aninformation stream, that is split into individual data packets at thelatest in the Internet Protocol, FIGS. 2 and 4 only show the principleof the method and not a necessary time scale.

Transmission Control Protocol (TCP) and User Datagram Protocol (UDP) areknown as IP-based transport protocols. TCP is used for transmittingdata, as the connection-oriented transport service TCP guarantees acomplete, error-free transmission with dedicated sequence of packets.The connection-free UDP offers a higher speed for transmission as theconnection set up, clear down and confirmation is not needed duringcommunication. With both UDP and TCP, the transmitted packets areassigned to the source and target applications via the ports.

The data part can comprise graphic data, other types of data or acombination of graphic data and other types of data. This means that thedata part may be significantly greater than the speech part. In thiscase or if an application makes greater demands on the transmissionspeed of the data part, then it may be sensible to use three ports forthe data part and one port for the speech part. For this type of use,the combination of ports must be planned into the definition.

The sender 10 and the receiver 40 may be video telephones or computerswith microphones. The interface units 20 and 30 may be gateways or anagent in a communication system, for which information streams occurwith information of a connection, mixed or unforeseeable with speech anddata parts. The information may be at the interface unit or alreadydivided into its component parts. The interface units can also be endunits, if the end units are a plurality of interfaces.

The invention has been described in detail with particular reference topreferred embodiments thereof and examples, but it will be understoodthat variations and modifications can be effected within the spirit andscope of the invention.

1. A method for Internet Protocol-based transmission of informationformed of a speech part and a data part in a communications systembetween interface units with a plurality of ports, comprising: obtaininginformation, divided into speech and data parts, at a first interfaceunit; compressing the speech part using a lossy algorithm andcompressing the data part using a lossless algorithm to obtaincompressed speech and compressed data; transmitting the compressedspeech and the compressed data from the first interface unit to a secondinterface unit, using different ports of the first interface unit forthe compressed speech and the compressed data, respectively; andreceiving the compressed speech and the compressed data at the secondinterface unit using dedicated ports corresponding to the speech anddata parts.
 2. A method according to claim 1, wherein more than two ofthe dedicated ports correspond to the speech and data parts.
 3. A methodaccording to claim 2, wherein said transmitting of the compressed datauses a Transmission Control Protocol.
 4. A method according to claim 3,wherein said transmitting of the compressed speech uses a User DataProtocol.
 5. A method according to claim 4, wherein the data partcontains graphics data.
 6. A method according to claim 5, wherein thedata part contains different types of data.
 7. A method according toclaim 6, further comprising dividing the information into the speech anddata parts in the first interface unit.
 8. A method according to claim7, further comprising: decompressing in the second interface unit thecompressed speech and the compressed data to obtain the speech and dataparts; and combining the speech and data parts in the second interfaceunit.
 9. A method according to claim 1, further comprising at the secondinterface unit: decoding the compressed speech and the compressed datain accordance with the lossy and lossless algorithms, respectively, toobtain decoded voice and data parts; and combining the decoded voice anddata parts to reproduce the information.
 10. A communication systemusing a transmission medium for Internet Protocol-based transmission ofinformation formed of a speech part and a data part, comprising: a firstinterface unit obtaining information divided into speech and data parts,compressing the speech part using a lossy algorithm and compressing thedata part using a lossless algorithm to obtain compressed speech andcompressed data and sending the compressed speech and the compresseddata using different ports for the compressed speech and data; and asecond interface unit receiving the compressed speech and compresseddata at dedicated ports allocated to the speech and data parts of theinformation.
 11. A communication system according to claim 10, whereinmore than two of the dedicated ports correspond to the speech and dataparts.
 12. A communication system according to claim 11, wherein saidfirst interface unit transmits the compressed data using a TransmissionControl Protocol.
 13. A communication system according to claim 12,wherein said first interface unit transmits the compressed speech usinga User Data Protocol.
 14. A communication system according to claim 13,wherein the data part contains graphics data.
 15. A communication systemaccording to claim 14, wherein the data part contains different types ofdata.
 16. A communication system according to claim 10, wherein saidsecond interface unit decompresses the compressed speech and thecompressed data in accordance with the lossy and lossless algorithms,respectively, to obtain decoded voice and data parts and combines thedecoded voice and data parts to reproduce the information.